Intra-oral scanner for digital impression and real-time reconstruction system for inner surface topographic image of oral cavity

Abstract

The present invention relates to medical devices and provides an intra-oral scanner for a digital impression. The intra-oral scanner has a window for limiting an acquisition range. The intra-oral scanner sequentially includes, along a light path, a three-color LED light source module, a microlens array sheet, a collimator lens group, a gray coding grating plate, an optical deflector, a projection lens group, a first reflector, a second reflector and a third reflector positioned in parallel with each other with their reflective surfaces opposing to each other, and a camera. The intra-oral scanner can perform a scan directly in the human oral cavity and obtain the digital impression of three-dimensional topography of the tooth and soft tissue in real-time, thereby meeting the requirements of dentists and dental technicians to quickly and accurately obtain the oral impressions.

What is claimed is: 
     
       1. An intra-oral scanner for a digital impression, the intra-oral scanner having a window for limiting an acquisition range, the intra-oral scanner sequentially includes, along a light path,
 a three-color LED light source module; 
 a microlens array sheet for making distribution of a light beam generated by the three-color LED light source module become uniform; 
 a collimator lens group for collimating the light beam; 
 a gray encoding grating plate for generating a gray encoded fringe pattern required for projection; 
 an optical deflector for offsetting the light beam such that lights of different wavelengths have different offset distance; 
 a projection lens group for projecting a gray encoded grating image passing through the gray encoding grating plate and the optical deflector onto a surface of an object to be measured; 
 a first reflector for redirecting the light beam so that projection lights are emitted through the window; 
 a second reflector and a third reflector positioned in parallel with each other with their reflective surfaces opposing to each other for ensuring a long distance transmission of the lights within a limited space; and 
 a camera for imaging, acquiring and recording a fringe distribution on an oral cavity inner surface. 
 
     
     
       2. The intra-oral scanner according to  claim 1 , wherein the three-color LED light source module comprises a three-color LED light source and a reflective bowl covering the three-color LED light source. 
     
     
       3. The intra-oral scanner according to  claim 1 , further comprising, before the camera, a fourth reflector and/or a fifth reflector for redirecting the light beam reflected by the second reflector and the third reflector such that the light beam is able to enter the camera. 
     
     
       4. The intra-oral scanner according to  claim 1 , wherein the optical deflector comprises a pair of wedge prisms having an identical shape and having a right-angled edge. 
     
     
       5. A real-time reconstruction system for an inner surface topographic image of an oral cavity, comprising an intra-oral scanner according to  claim 1 , and further comprising a computer system and a synchronizing circuit control system, wherein the synchronizing circuit control system controls synchronization of a strobe frequency of the three-color LED light source module with an acquisition frequency of the camera, and the computer system performs a real-time reconstruction of the inner surface topography of the oral cavity according to the fringe images acquired by the intra-oral scanner. 
     
     
       6. A real-time reconstruction system for an inner surface topographic image of an oral cavity, comprising an intra-oral scanner according to  claim 2 , and further comprising a computer system and a synchronizing circuit control system, wherein the synchronizing circuit control system controls synchronization of a strobe frequency of the three-color LED light source module with an acquisition frequency of the camera, and the computer system performs a real-time reconstruction of the inner surface topography of the oral cavity according to the fringe images acquired by the intra-oral scanner. 
     
     
       7. A real-time reconstruction system for an inner surface topographic image of an oral cavity, comprising an intra-oral scanner according to  claim 3 , and further comprising a computer system and a synchronizing circuit control system, wherein the synchronizing circuit control system controls synchronization of a strobe frequency of the three-color LED light source module with an acquisition frequency of the camera, and the computer system performs a real-time reconstruction of the inner surface topography of the oral cavity according to the fringe images acquired by the intra-oral scanner. 
     
     
       8. A real-time reconstruction system for an inner surface topographic image of an oral cavity, comprising an intra-oral scanner according to  claim 4 , and further comprising a computer system and a synchronizing circuit control system, wherein the synchronizing circuit control system controls synchronization of a strobe frequency of the three-color LED light source module with an acquisition frequency of the camera, and the computer system performs a real-time reconstruction of the inner surface topography of the oral cavity according to the fringe images acquired by the intra-oral scanner.